1. Field of the Invention
This invention relates to a dustproofing device or dustproof implement applicable to a clutch for transmission and interruption of driving force to a compressor which constitutes a part of an air-conditioning system for a working vehicle to be used in agricultural works or civil engineering works.
2. Description of the Prior Art
A working vehicle such as a large agricultural tractor is loaded with an air-conditioning system which aims at cooling and warming its operating space. This air-conditioning system works by rotationally driving a compressor forming a part thereof.
The compressor, like in case of a vehicle for another use such as an omnibus, is placed in the vicinity of an engine and is driven by receiving the rotational force of the engine. Also, in order to perform intermittent air-conditioning, a clutch for ON-OFF switching of the rotational driving state is attached to the compressor.
The clutch includes a plurality of parts surrounding a part of a housing of the compressor which surrounds an end of the rotation shaft of the compressor. In other words, the clutch includes a rotor rotatably borne by a part of the housing and provided with an annular recess opening toward the body of the housing; an annular coil received in the annular recess of the rotor and fixed on the housing body through an annular support plate surrounding the part of the housing; and a friction plate for mechanically connecting the rotor and the rotation shaft of the compressor.
The rotor of the clutch is rotated all the time by receiving rotational power of the engine through a belt. The coil, receiving the electric current, magnetizes the rotor and attracts the friction plate to the rotor. Due to the magnetic adsorption of the friction plate to the rotor, the rotor and the shaft of the compressor are mechanically connected, and the rotation force of the rotor is transmitted to the shaft of the compressor, thereby driving the compressor. On the contrary, when the electric current to the coil is stopped, the mechanical connection is released to stop driving the compressor.
In the working vehicle such as a large agricultural tractor, different from a car, there are many chances for dust, mud and the like to enter into gaps between the rotor of the clutch and the coil received in the annular recess due to the work and cause a rotation failure to the rotor.
Heretofore, to prevent such dust, mud and the like from entering, the support plate of the coil had a larger diameter, and an annular pad in contact with the rotor on the outer periphery side of the annular recess of the rotor was attached to the support plate.
However, the support plate of the coil having a relatively thick dimension was used, as it was required to support the relatively heavy coil, thereby resulting in an increase in weight of the compressor and clutch assembly and in cost to make the support plate having a large diameter. Further, when applying to a compressor and clutch assembly already loaded, there is such disadvantage as to necessitate replacement of a still usable coil.
An object of the present invention is, therefore, to provide a dustproof implement which restrains an increase in weight and cost of a compressor and clutch assembly when making a clutch to be attached to a compressor in an air-conditioning system loaded on a working vehicle dustproof,
Another object of the present invention is to provide a dustproof implement which does not necessitate replacement of a coil when applied to a compressor and clutch assembly already loaded on the working vehicle.
The present invention relates to a dustproof implement for a clutch which switches transmission of torque relative to the rotation shaft of a compressor constituting a part of an air-conditioning system of a working vehicle. The clutch includes a rotor borne by a part of a housing of the compressor and rotatable about the part, the housing surrounding an end of the rotation shaft of the compressor; and an annular coil received in an annular recess in the rotor and supported by the body continuous with the part of the housing through an annular support plate surrounding the part of the housing. The dustproof implement of the present invention applicable to such a clutch comprises an annular plate disposed between the support plate for the coil and the housing body and fixed at the housing body and opposing to the open face of the annular recess of the rotor so as to cover the open face; and an annular pad attached to the annular plate and contacting the rotor on the outer periphery side of the annular recess of the rotor.
Preferably, the support plate of the coil and the annular plate are fixed on the housing body with a plurality of machine screws penetrating through these plates.
According to the present invention, the dustproof implement is independent from the support body of the coil of the clutch to be attached to the compressor and is disposed between the clutch and the compressor body. The plate of the dustproof implement covers the annular recess of the rotor of the clutch and contacts the rotor on the outer periphery side of the annular recess of the rotor, whereby the annular recess is closed by the dustproof implement. As a result, dust and mud caused at the time of working by the working vehicle, on which the compressor and the clutch assembly are to be loaded, can be prevented from entering into the annular recess of the clutch, and a rotation failure of the rotor thereby can also be prevented.
The pad supported by the plate is far lighter in weight than the coil, the plate can be made very small in thickness and weight, thereby restraining a weight increase of the compressor and clutch assembly as well as an increase in manufacturing cost of the dustproof implement to the minimum.
In addition, even when a compressor and clutch assembly is already incorporated into the working vehicle, the dustproof implement made of a single substance can apply a dustproof measures to the clutch without necessitating any replacement of the coil of the clutch.
Further, the plate of the dustproof implement can be more swiftly and more securely attached to the compressor by fixing the plate of the dustproof implement on the housing body of the compressor together with the support plate of the coil of the clutch with a plurality of machine screws.